Social influence in a virtual tunnel fire e Influence of conflicting information on evacuation behavior * Max Kinateder a, * , Mathias Müller b , Michael Jost a , Andreas Mühlberger a, c , Paul Pauli a a University of Würzburg, Department of Psychology I, Marcusstr. 9-11, D-97072 Würzburg, Germany b VTplus GmbH, Germany c University of Regensburg, Department of Psychology, Clinical Psychology and Psychotherapy, Universit€ atsstr. 31, D-93053 Regensburg, Germany article info Article history: Received 30 September 2013 Accepted 26 May 2014 Available online xxx Keywords: Tunnel evacuation Social influence Virtual reality abstract Evacuation from a smoke filled tunnel requires quick decision-making and swift action from the tunnel occupants. Technical installations such as emergency signage aim to guide tunnel occupants to the closest emergency exits. However, conflicting information may come from the behavior of other tunnel occupants. We examined if and how conflicting social information may affect evacuation in terms of delayed and/or inadequate evacuation decisions and behaviors. To this end, forty participants were repeatedly situated in a virtual reality smoke filled tunnel with an emergency exit visible to one side of the participants. Four social influence conditions were realized. In the control condition participants were alone in the tunnel, while in the other three experimental conditions a virtual agent (VA) was present. In the no-conflict condition, the VA moved to the emergency exit. In the active conflict condi- tion, the VA moved in the opposite direction of the emergency exit. In the passive conflict condition, the VA stayed passive. Participants were less likely to move to the emergency exit in the conflict conditions compared to the no-conflict condition. Pre-movement and movement times in the passive conflict condition were significantly delayed compared to all other conditions. Participants moved the longest distances in the passive conflict condition. These results support the hypothesis that social influence affects evacuation behavior, especially passive behavior of others can thwart an evacuation to safety. © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved. 1. Introduction Road tunnel emergencies are rare yet potentially life- threatening events. After major tunnel fires in European road tunnels, new safety standards were developed (e.g., Directive 2004/ 54/EC) making road tunnels safer (Amundsen, 1994; Amundsen and Ranes, 2000). Safe tunnel evacuation requires adequate decision-making by tunnel occupants under time pressure and observations from recent tunnel fires document problematic occupant behavior (Burns et al., 2013). Prompt self-evacuation during tunnel fires is very important since tunnel fires can spread rapidly and differ significantly from other fire types in important aspects. Unlike in other open fires, vehicles can burn more vigorously due to heat feedback effects in the confined spaces of tunnels. In addition, the ventilation airflow may alter the ventilation flow pattern which can spread toxic gases and smoke over the tunnel. The ventilation system and other as- pects of the tunnel architecture affect the maximum heat release rate, the risk of flashovers, and the development of stratified smoke. Typically, the smoke moves in layers, away from the fire along the tunnel ceiling. Due to the smoke cooling down or to strong venti- lation, the smoke may spread down and mix with lower layers of air (For an overview, see Ingason, 2012; Purser, 2008). The formation of smoke influences the visibility in the tunnel, which in turn reduces walking speed and ultimately prolongs the evacuation time of oc- cupants (Fridolf et al., 2013a,b; Ronchi et al., 2011). Furthermore, smoke not only affects the visibility but is also a major threat to occupant safety since it contains large quantities of asphyxiant gases and irritants (Purser, 2008). The recommended behavior for tunnel occupants in case of a fire is to stop their vehicle at a safe distance (more than 50 m away) from the fire source on the side of the carriageway, switch off the * The data published here were recorded within the scope of the project “Pro- tection of critical bridges and tunnels” [Schutz kritischer Brücken und Tunnele SKRIBT Plus , FKZ: 13N9636], supported by the German Federal Ministry of Education and Research. The data of the manuscript is part of the dissertation of Max Kinateder. * Corresponding author. Tel.: þ49 9313188690. E-mail address: max.kinateder@uni-wuerzburg.de (M. Kinateder). Contents lists available at ScienceDirect Applied Ergonomics journal homepage: www.elsevier.com/locate/apergo http://dx.doi.org/10.1016/j.apergo.2014.05.014 0003-6870/© 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved. Applied Ergonomics xxx (2014) 1e11 Please cite this article in press as: Kinateder, M., et al., Social influence in a virtual tunnel fire e Influence of conflicting information on evacuation behavior, Applied Ergonomics (2014), http://dx.doi.org/10.1016/j.apergo.2014.05.014